The first episode Mark Gatiss wrote for the TV series, based loosely on his Big Finish Doctor Who episode "Phantasmagoria". Also, as the episode is set at Christmastime, the closest thing Christopher Eccleston has to a Christmas special on Doctor Who, even if the seasonal festivities are in name only.
The Cardiff rift remains open, and becomes a major feature of the Whoniverse from this point on.
The Doctor tries to take Rose to Naples, 1860. The TARDIS disagrees, and instead takes them to Cardiff, Christmas 1869.
Charles Dickens is in town, prompting an outbreak of earnest fanboyishness from the usually sardonic Ninth Doctor. The squee doesn't last the dead are walking, so the Doctor springs into action. It turns out that there's a massive space/time rift right in the middle of Cardiff. This will become important later. A young psychic maid named Gwyneth can guide things through the rift.
Dragging the very skeptical Dickens along, he organises a séance and negotiates with the aliens. If he helps them through the Cardiff Rift, they can temporarily occupy some corpses until he finds them a better home. Rose is Squicked, but the Doctor isn't in the mood to listen to some silly little human and coddle her delicate sensibilities.
The Gelth (as they call themselves) prove to be a bunch of lying promise-breakers, being "a few billion" in number and not being almost-dead. They were bent on wiping out humanity and taking over their corpses. The Doctor shows his raging Survivor Guilt over having previously killed a few species, most recently his own, and hesitates to jump into action. Gwyneth takes the decision out of his hands by sacrificing herself. Charles Dickens learns an important lesson about Christmas, and merrily bids the Doctor farewell, planning to include all sorts of ghosts and blue lights and aliens in police boxes in his novels from now on. The Doctor gloomily notes that nothing will actually change, though, because Dickens will be dead of natural causes within a year.
- Aliens in Cardiff: The first appearance of the Cardiff Rift.
- All Part of the Show: Mr Redpath's grandmother's face turns blue and the Gelth leave her body during Charles Dickens' reading of A Christmas Carol. Dickens tries to explain it away as "a trick of the lights". Unlike usual, though, the audience doesn't believe him and run.
- Arc Words:Gwyneth: [to Rose] The things you've seen. The darkness. The Big Bad Wolf.
- Asshole Victim: Sneed starts off concealing the fact that the bodies of the recently departed are moving about on their own. While understandable given these unexplainable occurrences, he goes from there to concealing at least one death, blackmails Gwyneth to protect himself, and kidnaps Rose.
- Attending Your Own Funeral: One of the Gelth-possessed corpses nearly did this.
- Beethoven Was an Alien Spy: Charles Dickens helping the Doctor fight alien ghosts.
- Bittersweet Ending: Although they prevail, the Doctor reminds Rose as they leave that Dickens is within a year of his death, and will not complete his next novel.
- Blatant Lies: When Rose confronts Gwyneth, she claims the old lady is suffering from "a brain fever", when said old lady is stone dead. Rose doesn't buy it for a second.
- Bottle Episode: The previous episode, "The End of the World", spared no expense as it was meant to retain viewers who had followed from the premiere. This episode was filmed in the same block as "The End of the World", and while there are special effects, note how this episode is a Period Piece to save money by using the BBC's already existing sets and costumes without having to create any.
- Can't Argue with Elves: Or, in this case, with the Doctor.
- Casting Gag: Simon Callow is a Dickensian scholar and has played Charles Dickens on several other programs.
- Changed My Jumper: The Doctor makes Rose change into something less distressing to Victorian sensibilities, but makes no changes to his own outfit except a new jumper. Nobody but Dickens remarks on the Doctor's attire, and he merely thinks the Doctor is just some navvy (labourer).
- Christmas Episode: Takes place on Christmas Eve, but very little Christmas-related happens apart from Dickens having a Scrooge-like rejuvenation.
- Condescending Compassion: Rose is sympathetic towards Gwyneth for her sad lot in life, and tries to give her advice on how to improve her situation. Except that Gwyneth doesn't feel her lot in life is particularly sad, and is insulted by the insinuation. Softened somewhat by the fact that Gwyneth can read Rose, and understands that this is simply due to Rose's background being fundamentally different from hers.
- Continuity Nod: As shown in the page quote, the Doctor mentions having seen the fall of Troy.
- Dead All Along: Gwyneth convinces the Doctor to leave so that she can stop the Gelth. The Doctor checks her pulse and escapes before she ignited the gas in the parlour. He later informs Rose and Charles Dickens that Gwyneth had been dead for several minutes.
- Dirty Old Man: Rose claims Mr. Sneed felt her up while loading her onto the hearse.
- Early Installment Weirdness: Meta example: it's the only Christmas Episode of the revival that isn't a special and aired in April.
- False Innocence Trick: The Gelth claim to be refugees from the Great Time War who have lost their bodies and only want to use dead humans as Meat Suits. It turns out that there are many more of them than they claimed, and they want to take over all humanity, not just the dead ones. Granted, they're not actually lying the key here is that they just need dead bodies. A few billion. Which means a majority (if not all) of the human population of Earth at the time.
- Follow That Car: After Rose is abducted in a hearse, the Doctor leaps into a nearby carriage and instructs the driver to follow that hearse. However, the carriage turns out to be a privately-owned vehicle, and the driver refuses to go anywhere without the say-so of his employer. Who turns out to be Dickens.
- Foreshadowing: The Doctor and Dickens talking about The Signal-man and A Christmas Carol.
- Ghostly Chill: The morgue cools down when the Gelth appear.
- Go Through Me:Gelth: We want this world and all its flesh!
The Doctor: Not while I'm alive.
Gelth: Then live no more!
- Great Offscreen War: The Gelth mention that the Time War wasn't visible to lower species, but it was to anyone sufficiently advanced enough, like themselves.
- The Greatest Story Never Told: Rose laments that no-one will ever know what Gwyneth did.
- Heroic Sacrifice: Gwyneth becomes the voice for the Gelth, who claim to wish to pass through a rift to Earth using her as a gateway in order to possess human corpses to regain physical form. The Doctor and Gwyneth agree, only for the Gelth to pour through the rift and reveal their true intentions of taking Earth by force. Gwyneth promptly traps the Gelth within the house, has the others flee, and lights a match, igniting the gaseous Gelth and destroying the house with her inside.
- Historical-Domain Character: Charles Dickens.
- Historical In-Joke: Dickens declares his intention to incorporate the Gelth into the climax of The Mystery of Edwin Drood, a novel that will go uncompleted because he'll die.
- I Was Just Passing Through: The Doctor claims this when Dickens inquires as to his true identity.
- Idiot Ball: The Doctor himself seems to be holding one when he urges helping the Gelth cross a space-time rift without even bothering to wonder why the corpses they have so far taken over all turned homicidal immediately. Possibly justified in that he feels responsible for the Gelth as victims of the Time War.
- I'll Take That as a Compliment: After Rose has changed into period-appropriate clothing:The Doctor: Blimey, you look beautiful... considering.
Rose: Considering what?
The Doctor: That you're human.
Rose: I think that's a compliment...
- I'm Your Biggest Fan: The Doctor to Charles Dickens. Bonus points for having to explain what a "fan" is.
- Innocuously Important Episode: The episode introduces the Rift in Cardiff. Without that rift, the events in "Boom Town", the show's first, third and fourth series' finales and "The End of Time" would not have taken place... nor any of Torchwood. There's also the fact that one of the main characters in Torchwood is named Gwen Cooper and is an implied lookalike relative of Gwyneth.
- In the Past, Everyone Will Be Famous: This was the first "Celebrity Historical" of the new series.
- Invading Refugees: The Gelth were fleeing the Time War.
- The Knights Who Say "Squee!": The Doctor squees at learning he's sitting next to Charles Dickens.
- Lame Pun Reaction: During a seance:The Doctor: Don't antagonise her. I love a happy medium.
Rose: I can't believe you just said that.
- Literary Work of Magic: At the end, Charles Dickens is inspired to write the episode's monsters into The Mystery of Edwin Drood so the world will know the truth. Of course, he suffers Author Existence Failure before finishing it.
- Names to Run Away From: The Gelth.
- Newspaper Dating: The Doctor uses a paper to determine that they are not, in fact, in 1860 Naples, but rather 1869 Cardiff. Rose doesn't care until she hears that last bit. "Right..."
- Nightmare Face: The Gelth◊, upon revealing their true colours.
- Noodle Incident: Apparently, the Doctor pushed boxes at the Boston Tea Party and fought in World War V.
- Not Using the "Z" Word: The Gelth aren't called ghosts in the story, which is fair enough since they aren't actually ghosts, just gas creatures. They can also possess human bodies for a little zombie action.
- Possessing a Dead Body: Recently deceased corpses are being inhabited by the Gelth, gaseous aliens who had lost their corporal forms. It gave the impression of ghosts possessing corpses to rise as zombies. While the Gelth initially feigned victimhood to invoke sympathy in the Doctor, they're later revealed to be malicious, as they desire all living humans to be dead so they can inhabit their bodies too.
- Psychic Powers: Gwyneth. They give her a connection to the Rift.
- Puppeteer Parasite: The Gelth.
- Reaction Shot: Rose glances at the Doctor when the Time War is mentioned. His face is unreadable, but she's right about there being a connection to the Doctor.
- Rebel Relaxation: The Doctor, while watching Dickens check out a corpse.
- Red Eyes, Take Warning: You know the Gelth aren't what they claim when the one speaking through Gwyneth changes from a soothing uniform blue to having red eyes.
- She Cleans Up Nicely: Rose dons a period-appropriate gown for the 19th century. The Doctor notices, before adding "considering".
- Shout-Out to Shakespeare: Dickens references Hamlet when the Doctor can't explain how Gwyneth had saved them in spite of the fact that she was dead.
- Spooky Séance: At the Doctor's suggestion, they hold a séance, presided over by Gwyneth, to contact the Gelth. She bases it on what she's seen the Spiritualists that she's gone to for advice on her powers do.
- Stealth Pun:
- Gwyneth addresses Rose as "the big bad wolf". Rose has come to 1869 Cardiff wearing makeup, which at the time was only worn by prostitutes, and "she-wolf" is an old slang term for one.
- "What the Shakespeare is going on?" said by Charles Dickens.
- Taking You with Me: Gwyneth and the Doctor realize that since the Gelth are using Gwyneth to enter our universe, she must sacrifice herself to stop them coming. The Doctor tries to talk her out of it, but she refuses. She closes the rift and destroys the malevolent gaseous beings by igniting the gas-filled (thanks to a previous attempt to stop the Gelth) air with a match, blowing up the house, the creatures and herself.
- Temporal Paradox: Rose thinks that this means the Gelth can't kill her in 1869, since she's still living in 2005. As the Doctor explains, however, time travel doesn't work that way her travel from 2005 to 1869 doesn't affect her ability to die.
- Wham Line: "Maybe your dad's up there too, miss" is one for Rose. She didn't mention her father at any point to Gwyneth.
- White Man's Burden: Subverted. In a temporal socio-economic version of the trope, Rose takes pity on Gwyneth and tries to stop the Doctor from "using" her to let the Gelth through. Gwyneth does not appreciate this, accusing Rose of thinking that she's stupid and unable to understand what is going on just because she didn't have an education.
- World War Whatever: The Doctor mentions having seen World War V.
- Yet Another Christmas Carol: Downplayed, but the elements are still there; adventures with ghostly creatures and time travellers help shake Charles out of his ennui.